Flag Zone is a logic puzzle in the family of the popular Queens game. The board is a square grid split into coloured regions, and your job is to plant one flag in every row, every column, and every colour region — with the extra twist that no two flags may sit in touching cells, not even diagonally. There is always exactly one correct arrangement, so every puzzle can be solved by pure reasoning without ever guessing.
A finished board obeys four rules at once: one flag per row, one per column, one per colour region, and no two flags adjacent (horizontally, vertically, or diagonally). Because the regions vary in shape and size, the colour rule is what makes each puzzle distinct — it forces flags into awkward positions that the row and column rules alone never would.
Tap an empty cell once to place a small ✕, your note that a flag can't go there. Tap again to commit a ⚑ flag. A third tap clears the cell. As soon as you plant a flag, the rest of its row and column are crossed out automatically, so you can see at a glance which cells are still in play. Most solvers fill in their own ✕ marks first to map out where flags are impossible, then the flag positions reveal themselves. Use ↩ Undo to reverse a move with no penalty, ✓ Check to flash any rule conflicts, and ⌫ Clear to wipe your marks and restart the same board.
Stuck? The 💡 hint button reveals one correct flag and removes any wrong flag in that row. Each hint adds a 30-second penalty to your timer, so use them sparingly if you're chasing a fast time or a clean three-star story rating.
Two independent dials let you tune the challenge. Choose a grid size from 5×5 up to 9×9, then set a difficulty from Beginner through Cyborg. Every size offers all seven difficulties, so a quick 5×5 Beginner makes a gentle warm-up while a 9×9 Cyborg is a deep logical workout. Harder difficulties keep the same board but reshape the colour regions to demand longer deduction chains with fewer obvious opening moves.
Flag Zone is a Queens-style strategy puzzle: place one flag in every row, every column, and every coloured region, with no two flags touching — not even diagonally. That last rule is what makes it sing, because it turns a simple placement task into a web of constraints where one flag rules out a whole neighbourhood of squares. Work through 7 difficulty ranks, take on the seeded daily, and climb the six-chapter story mode as the regions get gnarlier.
What makes it tick is the triple duty every flag pulls: place one and it claims its region, its entire row, and its entire column all at once. So a single correct placement can lock down a huge chunk of the board — and finding which square that is can be genuinely tough. But it's never not entertaining. There's a particular satisfaction in spotting the one flag that unravels everything else, and Flag Zone is built around hunting for exactly that.
The seeded daily means everyone solves the exact same board, so your time is a fair race. Flag Zone scratches the same deduction itch as the number puzzles, so if you like reasoning your way to the only valid answer, try Calcudoku or Nurikabe next.
I came across this puzzle in a magazine, where it was called Queens — and I got quietly obsessed with it in the way you only do with a puzzle that fits in your pocket. There wasn't a version of it I could carry around and share with people, so we built our own. That's Flag Zone: Cliko's build of the magazine Queens puzzle, with flags standing in for crowns and the same beautiful, compact rule set running underneath. Place exactly one flag in every row, every column, and every coloured zone — and no two flags may ever touch, not even diagonally. Four constraints, one unique solution, no guessing ever required. It's the kind of design that looks like nothing at all and then quietly eats your entire commute.
The player mistake here is the most common failure in all of logic puzzling, presented in its purest form: guessing-and-checking instead of hunting forced placements. A player stares at the grid, feels no obvious opening, plants a speculative flag somewhere plausible, and starts patching contradictions as they bloom. Three guesses deep, the board is a crime scene and none of the evidence means anything anymore. And the whole time, the puzzle was offering certainties — because the structure of these rules manufactures them constantly, on every board, at every size.
Here's the engine of it. Every zone, every row, and every column needs exactly one flag. So the moment any zone — or row, or column — is down to a single open cell, that cell is forced. Not likely. Forced. And here's why the cascade keeps running: each flag you place is a small explosion of eliminations — its entire row closes, its entire column closes, and every cell it touches, all eight neighbours, closes too. Those eliminations shrink other zones and lines, which forces new cells, which eliminate more. One genuinely forced flag can resolve a third of the board before the dust settles.
So the method is: chase the forced cells first, and keep chasing them relentlessly. Start with the smallest zones — a one-cell zone is a gift, a two-cell zone is nearly one. After every placement, re-scan for whatever just became forced, because something usually did. Only when the forcing genuinely runs dry should you even consider a hypothesis, and on these boards, honestly, it rarely comes to that.
Seven difficulty levels scale the grid and the zone complexity, and the daily puzzle at midnight is identical for every player. It started as a magazine page that wouldn't leave me alone. Now it's yours to not be left alone by.
One last habit from my magazine days: when a board finally stalls, don't stare harder at the empty cells — re-read the flags you've already placed. The elimination you missed is almost always radiating from a flag you stopped looking at two moves ago, and finding it feels better than any lucky guess ever could.